scholarly journals Effect of In-Mold Annealing on the Properties of Asymmetric Poly(l-lactide)/Poly(d-lactide) Blends Incorporated with Nanohydroxyapatite

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2835
Author(s):  
Martin Boruvka ◽  
Cenek Cermak ◽  
Lubos Behalek ◽  
Pavel Brdlik
Keyword(s):  
Tensile Modulus ◽  
Fracture Morphology ◽  
The Other ◽  
Degree Of Crystallinity ◽  
Material System ◽  
High Concentration ◽  
Other Hand ◽  
Bone Graft Substitutes ◽  
Injection Molded ◽  
As Stress

The proper choice of a material system for bioresorbable synthetic bone graft substitutes imposes strict requirements for mechanical properties, bioactivity, biocompatibility, and osteoconductivity. This study aims to characterize the effect of in-mold annealing on the properties of nanocomposite systems based on asymmetric poly(l-lactide) (PLLA)/Poly(d-lactide) (PDLA) blends at 5 wt.% PDLA loading, which was incorporated with nano-hydroxyapatite (HA) at various concentrations (1, 5, 10, 15 wt.%). Samples were melt-blended and injection molded into “cold” mold (50 °C) and hot mold (100 °C). The results showed that the tensile modulus, crystallinity, and thermal-resistance were enhanced with increasing content of HA and blending with 5 wt.% of PDLA. In-mold annealing further improved the properties mentioned above by achieving a higher degree of crystallinity. In-mold annealed PLLA/5PDLA/15HA samples showed an increase of crystallinity by ~59%, tensile modulus by ~28%, and VST by ~44% when compared to neat hot molded PLLA. On the other hand, the % elongation values at break as well as tensile strength of the PLLA and asymmetric nanocomposites were lowered with increasing HA content and in-mold annealing. Moreover, in-mold annealing of asymmetric blends and related nanocomposites caused the embrittlement of material systems. Impact toughness, when compared to neat cold molded PLLA, was improved by ~44% with in-mold annealing of PLLA/1HA. Furthermore, fracture morphology revealed fine dispersion and distribution of HA at 1 wt.% concentration. On the other hand, HA at a high concentration of 15 wt.% show agglomerates that worked as stress concentrators during impact loading.

scholarly journals The Effect of IP Constituent Position and Foot Complexity on Timing in Polish Learner's English Pronunciation

2010 ◽  
Vol 8 ◽  
pp. 149-162
Author(s):  
Andrzej Porzuczek
Keyword(s):  
Stress Distribution ◽  
The Other ◽  
Speech Timing ◽  
Other Hand ◽  
British School ◽  
English Pronunciation ◽  
Native Speech ◽  
As Stress

This paper focuses on the effect of prominence level and stress distribution on timing in read English speech of Polish learners. We have measured and analysed the length of IP units distinguished by the traditional British School prosodic description, i.e. preheads, heads and nuclei, as well as stress feet, further divided into stressed and unstressed syllables. A comparison of native and Polish learners' performance shows similar durations of stressed and pitch accented syllables. The unstressed syllables and syllable clusters, on the other hand, are significantly longer in non-native speech, and the discrepancies increase at lower phrasal prominence levels, especially in the preheads. Similar results for both groups have been obtained with respect to the number of consecutive unstressed syllables (foot complexity). The same test repeated after seven months of pronunciation training reveals a considerable tendency towards native speech timing, although the differences concerning low prominence levels remain significant.

scholarly journals HOG-Independent Osmoprotection by Erythritol in Yeast Yarrowia lipolytica

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1424
Author(s):  
Dorota A. Rzechonek ◽  
Mateusz Szczepańczyk ◽  
Guokun Wang ◽  
Irina Borodina ◽  
Aleksandra M. Mirończuk
Keyword(s):  
Transcription Factor ◽  
Yarrowia Lipolytica ◽  
Carbon Sources ◽  
Hyperosmotic Stress ◽  
Sensitive Strain ◽  
The Other ◽  
High Concentration ◽  
Other Hand ◽  
Yeast Yarrowia Lipolytica ◽  
Better Than

Erythritol is a polyol produced by Yarrowia lipolytica under hyperosmotic stress. In this study, the osmo-sensitive strain Y. lipolytica yl-hog1Δ was subjected to stress, triggered by a high concentration of carbon sources. The strain thrived on 0.75 M erythritol medium, while the same concentrations of glucose and glycerol proved to be lethal. The addition of 0.1 M erythritol to the medium containing 0.75 M glucose or glycerol allowed the growth of yl-hog1Δ. Supplementation with other potential osmolytes such as mannitol or L-proline did not have a similar effect. To examine whether the osmoprotective effect might be related to erythritol accumulation, we deleted two genes involved in erythritol utilization, the transcription factor Euf1 and the enzyme erythritol dehydrogenase Eyd1. The strain eyd1Δ yl hog1Δ, which lacked the erythritol utilization enzyme, reacted to the erythritol supplementation significantly better than yl-hog1Δ. On the other hand, the strain euf1Δ yl-hog1Δ became insensitive to supplementation, and the addition of erythritol could no longer improve the growth of this strain in hyperosmotic conditions. This indicates that Euf1 regulates additional, still unknown genes involved in erythritol metabolism.

Inhibitory effects of calcium ionophore pretreatment of porcine oocytes on polyspermic fertilization

Zygote ◽  
2006 ◽  
Vol 14 (1) ◽  
pp. 17-22 ◽  
Author(s):  
T. Hayashi ◽  
H. Sato ◽  
H. Iwata ◽  
T. Kuwayama ◽  
Y. Monji
Keyword(s):  
Calcium Ionophore ◽  
Inhibitory Effect ◽  
Calcium Ionophore A23187 ◽  
The Other ◽  
Ionophore A23187 ◽  
Inhibitory Effects ◽  
High Concentration ◽  
Maturation Period ◽  
Low Concentration ◽  
Other Hand

The present study examined the inhibitory effects of various pretreatment concentrations (0–100 μM) of the calcium ionophore A23187 on polyspermic fertilization and then examined the effect of the maturation period and the time between calcium ionophore treatment and fertilization on the inhibitory effect of calcium ionophore on polyspermic fertilization. In experiment 1, a high concentration of calcium ionophore (100 μM) increased the rate of activated oocytes, but the rate of fertilization declined. On the other hand, when oocytes were treated with a low concentration of calcium ionophore (10 μM), monospermic fertilization was significantly increased (10 μM; 31.3%) (p < 0.05). In experiment 2, oocytes were cultured for various times (0, 0.5, 3, 6 h) after calcium ionophore treatment (10 μM) before fertilization. The highest rate of monospermic fertilization was detected in the oocytes cultured for 6 h after calcium ionophore treatment before fertilization. In experiments 3 and 4, we examined the effect of the maturation period (40 h or 44 h) on the rate of fertilization and blastulation of oocytes pretreated with calcium ionophore. The treatment of oocytes with calcium ionophore significantly decreased the rate of polyspermic fertilization regardless of the maturation period (44 h: with calcium ionophore 26.25% vs without 78.8%; 40 h: with calcium ionophore 37.5% vs without 77.5%); however, calcium ionophore treatment increased the rates of monospermic fertilization and blastulation of the oocytes matured for 44 h, but not those matured for 40 h. In conclusion, activation with a low concentration of calcium ionophore (10 μM) and a further 6 h of culture before fertilization improved the rate of monospermic fertilization and blastulation.

Persistent Electronic Conduction in 12CaO7Al2O3 Thin Films Produced by Ar Ion Implantation: Selective Kick-Out Effect Leads to Electride Thin Films

2004 ◽  
Vol 811 ◽  
Author(s):  
Masashi Miyakawa ◽  
Katsuro Hayashi ◽  
Yoshitake Toda ◽  
Toshio Kamiya ◽  
Masahiro Hirano ◽  
...  
Keyword(s):  
Thin Films ◽  
Ion Implantation ◽  
The Other ◽  
New Method ◽  
Electronic Conduction ◽  
High Concentration ◽  
Electronic Conductor ◽  
Other Hand

ABSTRACTA new method to convert 12CaO7Al2O3 (C12A7) thin films to electronic conductor by hot Ar+ ion implantation has been developed and its mechanism is discussed. It was found that hot Ar+ ion implantation extruded free O2- ions in C12A7 films by kick-out effects at fluences higher than 1×1017 cm−2, which left electrons in the cages embedded in C12A7 crystal and produced high concentration F+-like centers (∼1.4×1021 cm−3). The resulting films show coloration and persistent electronic conduction with conductivities up to ∼1 Scm−1. On the other hand, fluences less than 1×1017 cm−2 kept the films transparent and insulating.

Viability and Adaptability of E. coli. and Enterococcus Group to Salt Water with High Concentration of Sodium Chloride

1982 ◽  
Vol 14 (4-5) ◽  
pp. 115-126 ◽  
Author(s):  
T Omura ◽  
M Onuma ◽  
Y Hashimoto
Keyword(s):  
Sodium Chloride ◽  
Salt Water ◽  
The Other ◽  
Type I ◽  
Citrobacter Freundii ◽  
Type Ii ◽  
High Concentration ◽  
E Coli ◽  
Rapid Extinction ◽  
Other Hand

Some experiments were carried out to examine the adaptability of E. coli. and enterococcus group to salt water with high concentration of sodium chloride after the experiments on viability in this salt water. Unlike E. coli. type I, when E.coli. type II was repeatedly exposed to salt water, the survival of E.coli. type II was changed from rapid extinction to multiplication as the experiments went on. At the same time, it was also made clear by means of the IMViC test that E.coli. type II was replaced by Citrobacter freundii as E.coli. type II adapted itself to salt water. The enterococcus group was separated into four distinct types; S. faecalis, S. faecalis var. liquefaciens, S. faecium and S. durans. The results of the experiments on viability in salt water indicated that S. faecalis var. liquefaciens possessed the greatest viability, and S. faecium the weakest. From the results of the experiments on adaptability, it was found that each type of enterococcus group had a different adaptability to salt water. In spite of the weakest viability, S. faecium could adapt itself to salt water as well as S. faecalis and S. faecalis var. liquefaciens. On the other hand, S. durans could not adapt itself to salt water at all.

Experimental Study on the Plasticizer Wastewater Treatment by UASB-A/O Process

2014 ◽  
Vol 955-959 ◽  
pp. 2574-2580
Author(s):  
Zhi Yong Yu ◽  
Jia Ze Bao ◽  
Jian Guo Jiang ◽  
Wu Sheng Ma ◽  
Jin Yao Yang
Keyword(s):  
Experimental Study ◽  
Wastewater Treatment ◽  
Optimal Condition ◽  
Removal Rate ◽  
The Other ◽  
High Concentration ◽  
Combined Process ◽  
Other Hand ◽  
Aerobic Zone

Plasticizer wastewater of high concentration was experimentally studied by the process of pretreatment of acidification demulsion and Fe-C micro-electrolysis and combined process of UASB and A/O aiming at the CODCr removal in this work. The result showed that the CODCr removal rate of pretreatment process arrived at 56.2% after Fe-C micro-electrolysis reaction of 160 min on the optimal condition of pH 3.5 of acidification demulsion and 1:1.2 of the Fe/C ratio, and meanwhile improved the biodegradability of wastewater. On the other hand, UASB-A/O process could afford 80~85% of the CODCr removal rate under the optimized condition of temperature 30~35 °C, HRT 48h, pH 6.5 for UASB and HRT of aerobic zone 10~12 h, DO of about 3mg/L for A/O basin. The whole system could run at the total CODCr removal rate of 94.53~96.36%, and the system effluent CODCr was 500 mg/L or less.

Numerical Study of CO and CO2 Emissions From Rural Kitchen in Developing Countries

2015 ◽  
Author(s):  
M. Hamidur Rahman ◽  
A. K. M. Sadrul Islam ◽  
M. Ruhul Amin
Keyword(s):  
Developing Countries ◽  
Natural Ventilation ◽  
Co2 Concentration ◽  
The Other ◽  
Breathing Zone ◽  
Forced Ventilation ◽  
High Concentration ◽  
Ventilation Condition ◽  
Other Hand ◽  
Source Concentration

In this study the pattern and varying intensity of CO and CO2 emission from different kinds of Biofuel used in the rural areas of developing countries have been investigated. A typical rural kitchen of dimension 3.0m × 1.5m × 2.2m is constructed with an improved concrete oven. We have measured the source concentration at the stove and used the value for the numerical model. In the current analysis it is observed that at closed ventilation condition, CO and CO2 concentration exceeds safe limiting value. Even under the natural ventilation, it fails to keep the concentration below the safe threshold. However in forced ventilation system at 5m/s, the concentration level drops significantly. At the breathing point, for a source concentration of 338 PPM and without any ventilation, numerical results predict the CO concentration to be 70 PPM. Natural ventilation case shows no improvement while forced ventilation suppresses the concentration by 70%. On the other hand, for a no ventilation condition, CO2 concentration is found to be as 2050 PPM when the source level concentration is 7100 PPM. Forced ventilation at 5m/s decreases the concentration to 750 PPM, well within the safe limit. High concentration was found to accumulate beneath the roof and on the top of the stove. It is then dispersed to the entire upper region of the kitchen. Deploying a duct in the exact spot shows that forced ventilation captures most of the fume and decreases dispersion along the roof. In no ventilation and natural ventilation cases, high concentration accumulation can be observed in the lower-left and lower-right corners, both in longitudinal and lateral planes which eventually affects the breathing zone concentration. On the other hand, for forced ventilation case, concentration at lower-left and lower-right corner is greatly reduced resulting low concentration at the breathing zone.

Study on N and B Doping by Closed Sublimation Growth Using Separated Ta Crucible

2019 ◽  
Vol 963 ◽  
pp. 34-37 ◽  
Author(s):  
Daiki Tanaka ◽  
Hiroaki Kurokawa ◽  
Satoshi Kamiyama ◽  
Tetsuya Takeuchi ◽  
Motoaki Iwaya ◽  
...  
Keyword(s):  
The Other ◽  
High Concentration ◽  
Other Hand ◽  
B Doping ◽  
Sublimation Growth

Boron (B) doping sources and crucible materials for stable, reproducible and high concentration B doping in fluorescent SiC (f-SiC) were investigated. When a Ta crucible was used with BN powder as a B doping source were used, B doping did not occur owing to too low C/Si ratio. On the other hand, when a C crucible and suitable Ta components inside the crucible were used, a high B concentration of 1.58 × 1019 cm-3 was obtained, owing to the high C/Si ratio. The results indicate that a C crucible with optimal Ta components and BN powder are suitable for high concentration B doping.

Converting stress to pressure

2017 ◽  
Author(s):  
Peggy D. Bennett
Keyword(s):  
Language Use ◽  
The Other ◽  
Self Determination ◽  
High Profile ◽  
Other Hand ◽  
As Stress ◽  
Self Protection

“I am totally stressed.” “This is so stressful.” How often do we say these words? What if, each time we announce that we are stressed, we are injecting ourselves with a toxic brew of chemicals? Stress is a high- profile affliction in this society and is often identified as the cause of various maladies we may contract. Many of us identify what we are feeling as stress simply because that is the easiest and most in- vogue terminology for our condi­tion. The term “stress” has been used to describe bad moods, fatigue, excitement, anxiety, and tensions. But do all those feel­ings equate with stress? Actually, no. Real stress is threat. Threat creates a primal response in which our body produces the necessary chemicals to enable us to fight or flee. “Threat is what some power, usually a person or group, can do and may very well do to harm us”. If we make a distinction between stress and pressure, perhaps the destructive impacts of stress will become clearer. “Threat is not the same as pressure— one may rush to catch a train or plane with worry and fear about missing it, but without threat”. The popularization of the term “stress” has taken a toll on us. Labeling our feelings as stressful can actually make them feel worse. Stress is unhealthy because it eats away at our armor of self- protection and self- determination. Pressure, on the other hand, can give us momentum to act. Unlike stress, “pressure can be a constructive, propelling force in our reactions to life situations”. “I’m feeling the pressure to get my reading done.” “The pres­sure to learn this new program is taking a lot more energy than I thought it would.” “I’m under a lot of pressure to make a deci­sion.” Pressure can be a contributor to resiliency. Try switching your language use from “stress” to “pressure” and see if that makes a difference in minimizing your image of worry or sense of threat.

The Concentration From the Competition Perspective in the Turkish Banking Sector

2020 ◽  
pp. 471-492
Author(s):  
Mustafa Tevfik Kartal
Keyword(s):  
Banking Sector ◽  
Concentration Level ◽  
Industry Structure ◽  
The Other ◽  
Entry Barriers ◽  
High Concentration ◽  
Other Hand ◽  
The World ◽  
Regulatory Bodies

With the globalization, the world has been becoming a much smaller place. New types of business have been emerging. Depending on this situation, new corporations are founded in current and emerging sectors. This causes an increase in competition. On the other hand, a variety of sectors are regulated intensively which result in a high concentration. Banking sectors is one of these sectors at where regulations are much and entry barriers are high. It is aimed at examining concentration from competition perspectives Turkish Banking Sector (TBS). It is concluded that TBS generally has a non-concentrated industry structure in terms of total assets, total credits, total deposits, total equities, and total net profits. Exceptions are seen in total net profits and in total deposits. Concentration level generally has decreased from 1999 (1,172 on average) to 2018 (899 on average calculated by Herfindahl-Hirschman Index (HHI). It is recommended that necessary precautions should be taken by regulatory bodies in order to decrease concentration and increase competition in TBS.

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